In the early 60s at BEA's insistence De Havilland downsized their Trident project to about 80percent of the 727 weight and thrust. By the late 60s BEA wanted to buy 727s and 737s but a political compromise was constructed whereby the Trident 3B with its RB-162 booster engine was purchased instead of the 727, and the BAC-111-500 instead of the 737. THe booster engine made the Trident 3B noisy. Some were exported to China